Uranium is a major subsurface contaminant at many US DOE sites. Subsurface sediments are heterogeneous mixtures of mineral phases, and evidences have suggested that multiple uranium hosts exist. However, spectroscopic investigation of U(VI) sorption on mineral mixture/assemblage is limited. In this work, batch sorption and cryogenic laser-induced time-resolved fluorescence spectroscopy investigation of U(VI) sorbed on a series of quartz-chlorite mixtures at varying quartz:chlorite mass ratios have been performed at field-relevant uranium concentrations (5x10-7 M and 5x10-6 M) in pH 8.1 synthetic groundwater. Our results indicated that the fluorescence spectra of U(VI) sorbed on the quartz-chlorite mixtures can be simulated by those of U(VI) sorbed on the pure mineral phases. However, the measured U(VI) sorption Kd values on the mineral mixtures were consistently lower than the calculated ones based on linear addition of the Kd values on the pure phases although the differences were small.

Cryogenic laser fluorescence spectroscopy investigation of  U(VI) sorption on quartz-chlorite mixtures

245th National Meeting (2013)

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